Variable Compression Ratio Engine Switchover Reliability

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Solution Overview

Problem

Existing reciprocating-piston machines with variable compression ratio experience unreliable transfer of the switchover element at high rotational speeds, leading to inadequate adjustment of compression ratios.

Innovation Solution

A reciprocating-piston machine with a sensor device and controller that detects deviations in compression ratio and activates an adjustment device to correct the switchover element, utilizing a slide or rotary element with multiple setpoint positions and actuating elements to ensure reliable switching, and incorporating sensors to measure combustion parameters for precise inference and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a hydraulically operated adjustment mechanism with switchover element is used to vary compression ratio, then the compression ratio can be adjusted between different setpoints, but the transfer of the switchover element becomes unreliable at high rotational speeds

Engineering Contradiction:

Improvecompression ratio adjustment capabilityVSAvoidswitchover element transfer reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a control device that receives signals from sensor devices about the actual compression ratio and compares it with the desired compression ratio. Based on this feedback, the control device activates the adjustment device to correct any deviations by actuating the switchover element to the appropriate switching position. This closed-loop feedback system ensures reliable compression ratio adjustment even at high rotational speeds where mechanical switching alone would fail.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the purely mechanical switchover mechanism with an electronically controlled system. Instead of relying solely on mechanical forces to transfer the switchover element, the system uses an actuator controlled by electronic signals from the control device. This substitution of mechanical switching with electronically actuated switching eliminates the reliability issues associated with high-speed mechanical transfer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Volume of moving object

If actuating surfaces run at an acute angle to the movement plane of the switchover element, then the switchover mechanism can be compact, but the transfer reliability decreases at high rotational speeds

Engineering Contradiction:

Improveswitchover mechanism sizeVSAvoidswitchover element transfer reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent replaces the mechanical acute-angle actuating surfaces with an electronically controlled actuator. The actuator receives activation signals from the control device and directly positions the switchover element without relying on acute-angle mechanical surfaces. This eliminates the fundamental flaw in the mechanical design while maintaining compact dimensions through precise electronic positioning.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from mechanical geometry (acute angle of actuating surfaces) to electronic control signals. Instead of relying on fixed geometric relationships that fail at high speeds, the system uses variable electronic signals to control the actuator position, allowing reliable operation across a wide range of rotational speeds while maintaining compact size.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If sensor devices and controllers are added to detect and correct compression ratio deviations, then switchover reliability increases, but device complexity increases

Engineering Contradiction:

Improvecompression ratio adjustment reliabilityVSAvoidsystem component quantity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into existing engine components. The control device leverages existing sensor devices already present in the engine for detecting operating parameters, and uses the existing actuator infrastructure for positioning the switchover element. By making these existing components serve the additional function of compression ratio verification and correction, the system achieves high reliability without proportionally increasing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10746107B2Variable compression ratio reciprocating piston engine

Publication Date: 2020.08.18 FEV EURO GMBH

AI summary

Reciprocating-piston machine (10), in particular a combustion machine, with a variable compression ratio, havingan adjustment device for adjusting the compression ratio,having a sensor device for detecting the compression ratio,and having a controller which is designed to repeatedly activate the adjustment device if a deviation and a detected compression ratio and a setpoint compression ratio exists.